Shaft coupling



R. C. DEHMEL SHAFT COUPLING Oct. 9, 1951 2 Sheets-Sheet 1 Original Filed Oct. 2, 1947 3 3 M5 2L 2. 3 F 1| 5 t. m E 8 3 2 8k 2. .R 5w Mm I I I W Z 8. t ,n t. r u I an 1/ I H U n F U 3 1 ATTORNEY.

R'. c. DEHMEL" SHAFT COUPLING- Oct. 9,1951

2 Sheets-Sheet 2 Original Filed Oct. 2, 1947 I lNVENTOR. m 50mg; C, DEHMEL m Mew 47 ATTORNEY.

Patented Oct. 9, 1951 UNITED STATES PATENT OFFICE SHAFT COUPLING Richard C. Dehmel, Short Hills, N. Y.

Original application October 2, 1947, Serial No. 777,414. Divided and this application July 16, 1949, Serial No. 105,163

Claims. (01. 6410) mitting smoothly and precisely rotary motion in I either direction through a plurality of closely groups interconnected units.

In accordance with the present invention, a pair of shafts disposed in general alignment is coupled by means of a resilient pin and slot connection mounted at adjacent ends of the shafts. The connection is made free of backlash by means of spring bias so that smooth angular transmission is obtained from the drive shaft notwithstanding reversal of rotation of the drive shaft and material misalignment of the drive and driven shafts. The connection occupies a very small space as compared with the conventional universal coupling so that the coupled shafts may be in practically abutting relation if desired. I

The invention will be more fully set forth in the following description referring to the accompanying drawings, and the features of novelty will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawings:

Fig. 1 is a view, partly in cross-section, of servo andpotentiometer units having a coupling embodying the present invention shown in connection with a simulated flight instrument;

Fig. 2 is an enlarged side view of the shaft coupling illustrated in Fig. 1;

Fig. 3 is a sectional view taken along the line 33 of Fig. 2, and;

Fig. 4 is a sectional view somewhat taken along the line 4-4 of Fig. 2.

In a practical embodiment of the invention shown in Fig. 1, a plurality of potentiometer units 13 and 14 such as those in servo computing apparatus for use in a flight simulating system of the character disclosed in my aforesaid application, Serial No. 777,414, are mechanically coupled so as to transmit angular motion from a driving servo motor 39, through the potentiometer units, to a simulated flight indicating inenlarged strument 24. The torque involved in the operation of such apparatus is comparatively small.v

but it is essential that the reversible servo motor transmit accurately and faithfully within. fine limits angular movement to the potentiometer units, which are in effect electrical precision instruments, and to the flight simulating instruf ment. The potentiometers control various com-'- puting circuits, a description of which is unneces-' sary for an understanding of the present invention.

A structural arrangement that may be conveniently used for a servo motor and potentiometer combination of the character above referred. to comprises a unit 25 having a pair of cylindrical housing sections 10 suitably secured together by end sections II and 12 and enclosing two groups of potentiometers generally indicated at 13 and; 14 respectively. The potentiometer resistance, elements such as 15 are wrapped on cylindrical insulating members 16 which vary in diameterso that they can be nested in concentric relation on the mounting plates 18 about the centrally located shaft sections 19 and 80.

mounting plates 18, which also form partitions in the housing serve as bearing supports for the contact carrying shafts l9 and respectively,

the shaft sections being coupled by a self-aligning connection 8| embodying the present invention.- for assuring comparativelyaceurate follow-up movement of the shaft 19.

The end section 12 supports a small motorgenerator set, the motor 39 being indicated, con-. nected to a flywheel 4| and reduction gear train.

42 for positioning the potentiometer contacts 11. The driving connection between the drive gear 82 of the gear train and the contact operating shaft 80 includes a simple friction clutch 83 of the spring washer type arranged to permit motor over-travel as well as manual adjustment of the that is connected to the rod 26 for operating the' pointer 24 of a simulated air speed meter 24.

The self-aligning connection 8| for'the potentiometer shafts l9 and 80 is shown in detail by 7 Figs. 2 to 4, misalignment of the shafts being exaggerated for purposes of illustration. .Al'-'- though universal couplings are well known, it

often happens that the shafts to be coupled are so closely spaced, due to requirements for very These shaft sections carry insulating supports H for the. coacting potentiometer slider contacts 11. Thecompact equipment, that conventional couplings cannot conveniently be used. The present coupling can be used in cases where the adjoining shafts practically touch each other, as in compactly arranged potentiometer groups for electric computing apparatus so as positively to connect the shafts without back-lash. Furthermore accidental slight relative longitudinal displacements of the shafts are automatically compensated without interfering with the proper transmission of movement.

Referring to Fig. 2, the drive shaft section 88 is provided at its free end 86 with an offset arm' 81 rigidly secured at 88 to the butt end of the shaft. The outer end of the arm carries an offset tapered pin-like member 89 extending toward the driven shaft 19 substantially parallel to the shaft lineup. The driven shaft '19 is also provided with an offset element, in this case a leaf spring or the like 96 secured at 9! to the adjoining butt end of the shaft. 19 The leaf spring 99 is normally biased toward the arm 81 and is bifurcated at its outer free end to form a narrow slot 92, Figs. 3 and l, in which the tapered end 89" of the pin rides as the spring follows up any inequalities of movement between the parts 8! and 90. Accordingly the tapered portion of the pin biased by its resilient mounting into continuous seating engagement with the complementary slotted portion precludes any play between the driving and driven parts. The slotted portion also permits limited relative radial movement of the pin in case of shaft misalignment. The preferred arrangement of the parts is illustrated although it will be understood of course that either arm may be resilient for the purpose described. Thus, the leaf spring and pin combination constitutes a resilient pin and slot connection for not only transmitting smooth angular movement to the driven shaft 79, but also eliminating back-lash or other objectionable relative movement between the shafts.

It will therefore be apparent that operation of the motor 39 in either direction causes both a corresponding change in the instrument reading and movement of the potentiometer contacts to different precise angular positions'on the respective potentiometer elements for deriving, i. e., picking 01f, potentiometer voltages corresponding to the contact position. The electrical connections for the terminals of each potentiometer and its associated contact are omitted in the interest of clearness.

It should be understood that this invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. A coupling for two shafts that are closely spaced end-to-end comprising an arm connected to one of said shafts in offset relation thereto, said arm having a slotted portion at its free end, a second arm connected in offset relation to the adjacent end of the other shaft, and a tapered member connected to said second arm for engaging said slotted portion so as to mechanically couple. said shafts, one of said arms being resiliently biased so that said member and slotted portion are urged into continuous engagement with each other at the tapered surface of said member so as to insure smooth angular drive notwithstanding limited misalignment of said shafts and to preclude back-lash between said shafts.

2. A coupling for two shafts disposed in near abutting end-to-end relation comprising an arm connected to one of said shafts in offset relation thereto, said arm having a slotted portion at its free end, a second arm connected in offset relation to the adjacent end of the other shaft, and a tapered pin connected to said second arm for engaging said slotted portion so as to mechanically couple said shafts, one of said arms comprising a leaf spring that is biased so as to urge said pin and slotted portion into continuous engagement at thetapered surface of said pin so as to insure smooth angular drive notwithstanding limited misalignment of said shaft and to preclude back-lash between said shafts.

thereto, said arm having a slotted portion at its freeend, a second arm connected in offset relation to the adjacent end of the other shaft, and a tapered pin connected to said second arm for engaging said slotted portion so as mechanically to couple said shafts, said resilient arm being biased into continuous engagement with said pin at its tapered surface so as to insure smooth angular drive notwithstanding limited misalignment of said shafts and to preclude back-lash between said shafts.

4. In servo apparatus having a plurality of closely grouped driven units with generally aligned operating shafts in near abutting relation, coupling means between said shafts for maintaining the same in substantially angular agreement notwithstanding limited misalignment thereof comprising a resilient member connected to one of said shafts in offset relation thereto and having a slotted portion at its free end, and a pin element mounted on the adjacent end of the coupled shaft also in offset relation and arranged to engage said slotted portion, said resilient member being biased into following engagement with said pin so as to preclude backlashbetween said shafts.

5. In servo apparatus having a plurality of closely grouped driven units with generally aligned operating shafts in near abutting relation, coupling mean between said shafts for maintaining the same in substantially angular agreement notwithstanding limited misalignment thereof comprising a leaf pring member connected to one of said shafts in right angle relation thereto and having a slotted portion at its free end, and a tapered pin secured to the adjacent end of the coupled shaft also in right angle relation and arranged to fit within the slot in said spring member, said spring member being biased into following engagement with said pin at its tapered surface so as to preclude back-lash between said shafts.

RICHARD C. DEHMEL.

Country Date Netherlands 1944 Number 

